Does it actually work? My experience in Europe (well a few places at least) is that most blue collar workers don't eat lunch in a restaurant, it's way too expansive (and time consuming). They either pack it from home, go to the local grocery/convenience store or maybe hit a fast food place/cheap take away.

It might work better in cultures with a more developed eat-out culture like in Asia.

I mean, I used to work in SF, in North Beach¹. Fisherman's Wharf is the tourist trap, and it's like right there, and in the years I worked for, never ate there. (I've been there as a tourist though.)

For lunch we'd hike over the hill into little Italy, and there was a decent sandwich shop we'd get lunch at. (Freddy's) Before the hill there was a small asian couple who ran a small shop, they made a good mushroom stew. No idea if they're still in business, though, or what their place was called.

Neither were restaurants … you weren't going to be finding a seat at least inside. There's plenty of seating around SF though, if you know where to look.

¹although Google thinks NB is actually a bit W of where we were.

around here the police tend to go in restaurants I like (atlanta)

Wouldn't it make sense to use something like Google Maps, filter to the lowest one or two price categories, and go from there?

I'd figure Google Maps, being less explicitly targeted to tourists, would be likely to include reviews and pricing data relative to a local mentality, which might not be so willing to spend tourist prices.

It's easier, I suppose, if you're doing a walking/public transit oriented trip and are in a city-- if you don't like what you see when you close in, just go 50 metres further down the street.